Police in the US have released thousands of pages from the investigation into the Newtown, Connecticut school massacre.
They provide the most detailed and disturbing picture yet of the rampage, Adam Lanza's chilling fascination with murder and school employees' attempts to protect children.
Included in the file were photographs of the home that the 20-year-old Lanza shared with his mother.
They show rounds of ammunition, gun magazines, shot-up paper targets, gun cases, shooting earplugs and a gun safe with a rifle in it.
A former teacher of Lanza's was quoted as telling investigators that Lanza exhibited anti-social behaviour, rarely interacted with other students and obsessed in writings "about battles, destruction and war".
"In all my years of experience, I have known (redacted) grade boys to talk about things like this, but Adam's level of violence was disturbing," the teacher told investigators.
The release of the documents marks the end of the investigation into the December 14, 2012 shooting at Sandy Hook Elementary School that left 20 young children and six educators dead.
Lanza went to the school after killing his mother, Nancy, in their home. He committed suicide with a handgun as police arrived at the school.
In a letter accompanying the files, Reuben F Bradford, commissioner of the State Department of Emergency Services and Public Protection, wrote that much of the report was disturbing but that it also showed teachers trying to protect their children, law enforcement officials putting themselves in harm's way and dispatchers working calmly and efficiently.
"In the midst of the darkness of that day, we also saw remarkable heroism and glimpses of grace," he wrote.